// 云函数入口文件
const cloud = require('wx-server-sdk')

cloud.init()
const db = cloud.database()
const _ = db.command
const $ = _.aggregate
// 云函数入口函数
exports.main = async (event, context) => {
  return await db.collection('posts')
  .aggregate()
  .project({
    _id: 1,
    _openid:1,
    commentnumber:1,
    viewnumber:1,
    content:1, 
    createTime:1,
    time:1,
  })
  .sort({
    createTime: -1
  })
  .lookup({
    from: 'users',
    localField: '_openid',
    foreignField: '_openid',
    as:'postedBy',
  })
  .match({
    _id:event.postid,
    _openid: event.openid
  })
  .skip(event.skiplength)
  .limit(25)
  .end()
}